The Market for Tablet Computers Has Grown Rapidly Over the Past

The market for tablet computers has grown rapidly over the past few years. Following the successful launch of the iPad in 2010 with nearly 20 million sales and growing to 310 million in 2016, companies such as Samsung, Dell, Microsoft, Amazon, Google and many others have all introduced products to compete with the iPad. The tablets introduced to compete with the iPad would be considered:

A) complements to the iPad.
B) substitutes for the iPad.
C) inferior goods compared to the iPad.
D) normal goods compared to the iPad.